1. Field of the Invention
The present invention relates to a switching mode power supply apparatus and an image forming apparatus that incorporates the switching mode power supply apparatus.
2. Description of the Related Art
A conventional image forming apparatus incorporates a power supply apparatus and a printer apparatus that operates on the power supply apparatus. The power supply apparatus is configured to receive an AC power through a main switch and convert the AC power into DC power. When an abnormality occurs in the printer apparatus, the printer apparatus sends an alarm signal to the power supply apparatus.
Japanese Patent Publication No. H10-27072 discloses a technology in which when an abnormality occurs in the load of a power supply apparatus, the power supply apparatus is switched off.
Such a conventional image forming apparatus has an AUTO OFF function in which if the printer apparatus is idle for more than a predetermined period of time, the power supply apparatus is automatically switched off. This type of image forming apparatus suffers from the following drawbacks.
Upon occurrence of an abnormality, the printer apparatus sends an alarm signal to the power supply apparatus, which in turn is automatically switched off. The power switch is then shifted to “OFF.” When the power switch is again shifted to “ON,” the AC power is not supplied until a certain period of time elapses before the power supply apparatus is released from the latched state. This is true for an auto-off function if the auto-off function is added to the power supply apparatus. This is inconvenient.
One way of solving this drawback may be releasing the power supply apparatus from the latched state in a shorter time. However, a shorter releasing time is detrimental to safe operation of the power supply apparatus. Accordingly, a need exists in the art for a solution to the aforementioned drawbacks.